This weekend, a teenage girl joins the ranks of Pixar heroes — alongside an old man in a floating house, a superhero gone to seed, a robot, a car, a toy cowboy, a monster, an insect, a fish and a rat.

Next to such a list, Merida does not look at first glance like a particularly adventurous choice of protagonist for "Brave," the latest film from hit machine movie studio Pixar. She is, after all, an adolescent princess, a staple character of children's movies for decades.

But Merida, with her flaming hair, impressive archery skills and feisty Scottish brogue, is both a departure for the studio that created her and a powerful addition to what is becoming a cinematic trend in 2012: a new wave of action heroines.

Pixar has never had a heroine at all. Its protagonists, with all their variety in species, shape and personality, have until now been exclusively male. This particular heroine, however, is in good company on the broader movie landscape. She is one of a quickly rising tide of fighting females at the box office, whose creators offer relatable portraits of young women with both strength and compassion.

Daring to move beyond traditional movie tropes, which dictate that female characters must either be highly sexualized or victimized, Merida and some of her current box office companions are offering audiences a change, and 2012 could be the year of the real girl.

The damsel in distress

In 1979, according to a recent study by Dr. Kathryn Gilpatric of Palm Beach State University, action movies changed to make room for heroines when Ridley Scott's "Alien" starred Sigourney Weaver as Lt. Ripley.

"It is now commonplace to see female action characters engage in hand-to-hand combat, wield swords, shoot machine guns, and employ high-tech weaponry to destroy people and property — once the exclusive domain of male action heroes," she wrote.

But Gilpatric's study examined whether women shooting at things ultimately challenged any stereotypes of female characters, and femininity in general. Gilpatric analyzed 300 films — the top 20 most popular action movies each year between 1991 and 2005 — to see if any female action characters appeared and how they behaved.

The results, released in spring 2010, concluded that just ratcheting up women's potential for violence did not necessarily change her role.

"The findings suggest," Gilpatric wrote, "that (female action characters) seem to be inserted into the story to support and promote the actions of the male hero. (She) often appeared as a damsel-in-distress providing the impetus for a male hero to overcome obstacles in order to save her."

More disturbing for Gilpatric was how often these characters went from potential to literal victim. Almost 30 percent of the figures studied died by the end of the movie. Additionally, 47 percent of these characters were villains and "consequently killed as punishment for their bad acts."

The author concluded that "due to the success and popularity of the action genre, which is disseminated to a broad audience both nationally and internationally, we need to be concerned with continued gender stereotypes set within a violent framework."

Putting a gun in a female character's hands does not promote independence and self-respect, or challenge the dominance of men in action movies.

Sexualized protagonist

Gilpatric's findings are not the only criticism of female action characters around. Dr. Jeffrey Brown, a professor of popular culture at Bowling Green State University, published his book "Dangerous Curves: Action Heroines, Gender, Fetishism and Popular Culture" just last year.

His criticism of the genre adds to Gilpatric's. Even when women in action movies are fighting for their own causes and taking their own shots, rather than cheering on the sidelines or acting as the love interest, the way they are portrayed and costumed is not exactly respectful, Brown argues.

"The standard uniform is a tight latex bodysuit," he said.

Brown pointed out that after the startling success of strong female action heroines like Ripley and Sarah Connor of the "Terminator" films, filmmakers seemed to shift focus in the 1990s and 2000s to making sure its women were overtly sexualized.

"I always found it strange that Hollywood moved away from that," he said.

"Whether portrayed in live action film and television by supermodels and centerfolds, in cartoons by anime-inspired wide-eyed preteen waifs, or stylized polygons and pixels in digital games, action heroines are conventionally beautiful, glamorous and sexualized," Brown argues in his book.

He, like Gilpatric, concludes that merely including female characters in fighting in action movies does not by itself provide examples of independence or strength. If these characters are dressed almost exclusively in skimpy outfits, they are objectified rather than empowered.

"It's really changing right now, isn't it?" said Gilpatric. "My findings aren't really applying. It's like the year of the woman."

Indeed, some of the most popular films of the year so far feature genuine action heroines who are neither overly sexualized nor sidelined. Katniss Everdeen of "The Hunger Games," a massive box-office success, is a particularly resonant character for both Gilpatric and Brown.

"'The Hunger Games' is a good example," Brown said. "They don't play up her sexuality in any ridiculous way."

Wrote Angela Watercutter in Wired magazine, "Her brain is as sharp as the arrows in her quiver … and her heroism isn't necessarily something that's played up as sexy. (Jennifer) Lawrence (who plays Katniss) is a beautiful girl, but she's a good Katniss because she's an incredibly multifaceted actress, not because she looks good holding a weapon in spandex."

Katniss, importantly, is also not violent out of vengeance or ambition, but because it is demanded for her survival. "She's a hunter, not a killer," said Lawrence of her character in an interview with Vanity Fair.

Katniss is perhaps the most popular but not the sole example of this new wave. "Snow White and the Hunstman," which has so far grossed more than $125 million, features its heroine, Snow White, as exuding what New York Times film critic A. O. Scott refers to as "modest, real-girl appeal," rather than beauty of an unattainable degree. She both leads forces into battle and, like Katniss, is as much a symbol of compassion as fierceness.

Enter Merida. "Passionate and fiery, Merida is a headstrong teenager of royal upbringing who is struggling to take control of her own destiny," state the press notes on "Brave." Like the others, Merida is not present to be ogled but rather to be admired.

"I wanted a real girl," the film's first director, Brenda Chapman, told the New York Times recently. "I wanted an athletic girl. I wanted a wildness about her … I wanted to give girls something to look at and not feel inadequate."

Brown is hesitant to say that the influx of positive action heroines this year will permanently alter Hollywood tradition, pointing out that while these films have been quite successful, so has "The Avengers," which features "Scarlett Johansson in a black bodysuit … flirtation really seems to be her power."